They paid fifty percent of _____ they were able to earn to the state.
Would you like to remind me _______ the medicine tomorrow?
The theory he sticks to ______ to be of no use in our studies.
____ that caused him to serve dinner an hour later than usual.
---- Do you know his address?---- No, I also wish I _____ where he _____.
—John has put forward _______ most challenging question for us to answer.—Yes, it really is. I have never heard _______ harder one.